8 Chemicals You’ll Need to Start Up Your Swimming Pool


Starting a pool up, either for the first time or for the season, is a big task. Between the cleaning and chemicals for a pool start-up, it is hard work for any pool owner.

Pools are seasonal in most areas of the world. Weather and climate sadly necessitate most being closed for certain periods of the year. This is bound to make start up difficult.

If you consider how much work goes into weekly pool maintenance and maintaining your pools chemical balance, it isn’t surprising that a dormant pool requires quite a bit of work to be safe for use again.

Using the right chemicals when staring a pool up will get your water off to the right start. The rest of the season can go well, with only need maintenance work needed to keep your water in good health. However, if you get things wrong the entire start-up could drag out as you attempt to fix your pool’s water.

What chemicals you need for a pool start up is actually going to vary on a few things, like what water you’re filling your pool with. However, testing your water should give you all the information to get things done right.

What Chemicals Are Needed for A Pool Start Up?

When you’re finding the chemicals you need for a pool start up, it all starts with your water.

Ideally, you should have properly cleaned your pool prior to filling it back up. Going through a full pool cleaning before filling it back up will cut down on contaminants in your water, equally a pool maintenance service can ensure chemically balanced water on start-up.

If you are filling from a freshwater source, it isn’t going to be perfect pool water. It would be a bit ridiculous to use entirely purified water too, so this is something you’re going to have to deal with.

The first thing that you need to do is test your water. While you can do this with a small test, it is better to go all-in with a full water test.

You need to know exactly what it is that you’re working with if you want to start your pool up right.

The Perfect Chemical Balance for a Pool Start Up

Chemicals for Pool Start Up

To decide what chemicals you need to use to start up your pool, you need to know what you’re working with. This is a good target for pool water.

  • pH – 7.2-7.6
  • Alkalinity – 80-120 ppm
  • Calcium Hardness – 180-220 ppm
  • Cyanuric Acid – 30-50 ppm
  • Chlorine – 1-3 ppm

It is quite unlikely that your pool will hit these targets as soon as it’s filled. If by some bizarre miracle your water comes out at this level, you don’t need to do anything to your pool!

Otherwise, you need to make a good note of your actual readings. Keeping a record of how your pool was when filled up will help you control the amount of chemicals you add.

How Many Chemicals Do You Need to Start Up Your Pool?

Once you know the state of your pool prior to start up, you can start to add and adjust the chemicals in your pool. The amount of chemicals for pool start up that you need to use is going to depend on what state your water is in.

Each chemical that you add to your pool needs to be doing something to the water to help it reach those targets. However, you need to be careful of chemical interactions and not overload your pool all at once.

These are the chemicals that you might have to add to your pool to get it in working order.

Alkalinity Adjusting Chemicals for Pool Start Up

Chemicals for Pool Start Up

If your pool’s initial test shows an incorrect amount of alkalinity, then you need to add some chemicals to fix it. It doesn’t matter if it was too high or too low, chemicals are going to be needed.

This should be the first chemical that you add to your pool during start-up. This one can really affect the pH level of your pool. Sorting this out first prevents you from ruining your hard work on your pool’s pH level by doing it afterward.

Alkalinity Increaser

Alkalinity increaser is going to be needed if your levels are below 80 ppm. Add this in safe increments until your water reaches this level.

pH Decreaser

If your alkalinity is too high, then you will need to use pH decreaser to lower it. This will affect the overall pH level in your pool, so it is best to do this before adjusting that level. This should avoid causing more problems.

You need to use this chemical if your alkalinity level is above 120 ppm. The ideal range for this chemical for pool start-up is between 80 and 120 ppm. You will need to use these chemicals to reach this level.

pH Adjusting Chemicals for Pool Start Up

Chemicals for Pool Start Up

Your pH level is really important for keeping your pool in good working order. If this is off, then your chlorine won’t be working properly which can lead to unsafe water and too much chlorine.

Your pH level should be the second thing that you address when adding chemicals. The ideal range is between 7.2 and 7.6. This is perfect for your chlorine and for keeping your water safe for use.

If your pH level is too high, you can use the same pH decreaser that you would use for adjusting alkalinity. Be sure to check that level again afterwards.

pH Increaser

pH increaser is a pretty simple chemical really. It increases the pH level of your pool water!

If your pH level is too low, then you need to add this to your pool. Otherwise, your water is too acidic. Not only is this not great for swimming in, but it can become corrosive. If your pH level is too low for too long, this can impact the rest of your pool’s maintenance.

Calcium Adjusting Chemicals for Pool Start Up

After addressing your pool’s alkalinity and pH level, you need to asses the calcium levels in your pool. Calcium isn’t typically a concern for ongoing pool maintenance. However, it does need to be assessed regularly, and this includes pool start up.

Calcium Hardness Increaser

This chemical helps to increase the calcium hardness level in your pool. If your level is below 180-220 ppm then this needs to be added.

This rule isn’t as strict as some of the others since the hardness level doesn’t have as many bad effects as some other chemicals. However, start up is about getting your pool in great shape, this includes going the extra mile on your chemical balance.

Muriatic Acid

This is a chemical that will lower your calcium hardness if it is too low. However, it needs to be used with caution.

Muriatic Acid is a chemical for pool-start up that will change your alkalinity level as well as calcium. This means that after you’ve gotten your calcium hardness in the right range, you might need to return to step one and readjust your alkalinity.

While this is a bit of a hassle, it is worth it in the long-run.

Cyanuric Adjusting Chemicals for Pool Start Up

This is the next step in getting the chemicals in your pool set up. This one addresses something that isn’t often tested in pool water, the cyanuric acid.

Most pools should have very little of this in them at start up. This builds up over time because of the chlorine added. The stabilizers are in the chemicals that you add to your pool water. These accumulate in your pool and affect the water.

This does take a while to build up, but testing for and correcting any of it found is important for a fully successful start up.


You only need to add this chemical if you’re using free chlorine. However, quite a lot of people do use this type of chlorine for pool start up.

You should add Stabilizer to bring your level up to 30 ppm to protect free chlorine that you’ve added into your pool. Otherwise, sunlight can stop it from functioning effectively and leave you with a dirty pool.

Chlorine for Pool Start Up

Chemicals for Pool Start Up

This might be the most important pool chemical that you have to use. Chlorine keeps your water clean and safe for use.

Too much chlorine though, can make your water sting and damage the skin of anyone who swims in it. This is definitely something you want to avoid. Fe people are convinced that the stink of chlorine is worth it for a cleaner pool!

You need to raise your chlorine level quickly during pool start up. This is a type of shock treatment that should get your water clean without degrading any of your other chemical levels.

When adding chlorine, you need to follow the instructions of the manufacturer for dosage and how long to leave the chemical before adding more. It is important to be careful with it.

Chemicals are Vital for a Successful Pool Start Up

The chemicals for pool start up are really important for getting everything off on the right foot. Without doing this properly, your pool start up can turn into a lengthy ordeal.

However, to get this chemical balance right quickly, you need to have a clean pool. This cuts down on contaminates in your pool water and lets the chemicals work properly.

This can be a complicated job, which is why a lot of people use pool maintenance services for the start up and close down of their pools. This ensures your pool starts off right, and you can keep on top of chemical maintenance through the season.

Otherwise, you can sort the chemicals for pool start up yourself. However, it is going to take some precision and quite a few chemicals.

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